Twisted tuft end brush and method of making

ABSTRACT

A twisted knot tuft wire filament end or cup brush suitable for carbon removal on engine blocks, for example, activates a longer useful service life by utilizing a center core formed into the center of the brush and conforming to and embracing the inner ends of the twisted tuft knots as they project from the cup. The core is applied in a putty-like condition and preferably with axial pressure. The core cures into a solid though somewhat elastic plug embracing the individual knots at the center of the brush and confining them against the cup wall. The invention substantially reduces fracture and particularly long fracture of the wire filaments significantly increasing brush life.

DISCLOSURE

[0001] This invention relates generally as indicated to a twisted tuft end brush and a method of making, and more particularly to a knot style twisted tuft wire end or cup brush having a significantly longer useful life and significantly better operating characteristics. The invention also relates to methods of making the wire knot style brush.

BACKGROUND OF THE INVENTION

[0002] Twisted tuft or knot type wire end or cup brushes are particularly effective in spot facing or cleaning, conditioning, abrading or finishing metal surfaces. They are particularly used in cleaning and de-burring operations. One good application is carbon removal on engine blocks. The twisted knot type brush is particularly aggressive in that the tips of each filament at the working face extend at a slightly different angle brought on by the twisting knot formation of each tuft. Thus each filament extends in a generally helical fashion.

[0003] Such brushes are usually formed. by inserting a bundle of wire filaments through equally spaced peripheral holes in a retainer plate. The bundles are then folded and the then two parallel portions are twisted together to form the twisted tuft knot. The inner portion of the tuft is in the form of a loop extending through the hole.

[0004] The retainer plate with the tufts in place is then inserted into a cup and secured in place usually by a swaged stud or pin projecting through a center hole in the plate. This assembly process causes the twisted knot-type tufts to project axially of the cup beyond its rim in an annular row around the interior of the cup. A sleeve may be inserted into the center of the cup primarily for confinement and to ensure the tufts remain parallel axially of the cup. The bottom of the cup is provided with an axially projecting arbor which may be secured to the spindle of an air or electric driven hand or bench type tool. Examples of this type of wire brushing tool are seen in U.S. Pat. Nos. 2,062,047 and 2,755,496.

[0005] Since the filaments are most tightly bent at the inner end where they form a loop, excessive movement along the inner end of the knot may create stress fractures of the filaments creating what is known as a long fracture. In this case substantially the entire filament above or in groups may break off and come out of the tool. Even if only one filament breaks it means two are loose since each wire forms two projecting filaments. Long fractures are in contrast to much shorter fractures which occur at the tip or working face as the brush wears back in use. Long fractures not only create safety problems but significantly shorten tool life.

[0006] Twisted tuft filament knots are generally circular in transverse section and if a sleeve or other metal type core is employed it will only engage the knot at a tangent point, and excessive localized pressure may tend to make the stress fracture problem worse.

[0007] There is a need for a low cost twisted tuft wire filament end or cup brush which will have a significantly longer service life, and better operating characteristics.

SUMMARY OF THE INVENTION

[0008] A twisted knot tuft wire filament end brush achieves both a longer useful life and more aggressive operating characteristics by forming a non-metallic plug or core in the center of the tool which embraces the inner ends of the knots. The core may be introduced as a putty or viscous liquid and may be pressed to conform to and embrace the inner ends of the knots. This process is facilitated by use of a retainer plate having alternating fingers and notches. Each finger includes an upturned end forming a radius corner with the knot hole extending in wrap-around fashion through the radius corner. The plug or core material preferably provides a tensile shear strength of from about 800 to about 1000 psi, a modulus of elasticity of about 6×10⁵, a hardness on the shore D scale of about 60-90, and should maintain its stability up to 300° F. or more. One preferred material is an epoxy resin.

[0009] To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is an exploded view of the cup and twisted wire tuft knot retainer disk of the brushing tool of the present invention, both in quarter section prior to assembly;

[0011]FIG. 2 is a diametrical section of the tool with the knots formed and the retainer disk secured to the bottom of the cup;

[0012]FIG. 3 is a similar section showing the putty-like core and being compressed during the manufacturing process;

[0013]FIG. 4 is a similar section of the completed tool;

[0014]FIG. 5 is a transaxial section through the core as seen from the line 5-5 of FIG. 4 showing the configuration of the core;

[0015]FIG. 6 is a similar section seen from line 5-5 of FIG. 4 showing the core compressed to a greater extent;

[0016]FIG. 7 is a view like FIG. 4 but showing a core applied in a viscous liquid form; and

[0017]FIG. 8 is a transaxial section of the tool of FIG. 7 seen from the line 8-8 thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] Referring initially to FIG. 1 there is illustrated the cup 10 and knot retaining disk 12 which retain and secure the twisted wire tufts in place.

[0019] The cup 10 includes a cup bottom 13 from which projects the annular peripheral cup wall 14 terminating in slightly flared lip or rim 15. The bottom is thickest at its center axis and tapers uniformly to its thinnest portion from which the cylindrical wall 14 extends. Projecting axially from the bottom of the cup in the opposite direction is stem or shank arbor 17 which may be secured by a suitable collet to the rotor of an electric or air motor driven hand tool, for example, or a similar power driven bench or table tool. In this manner the end or cup brush tool may be rotated about its axis at relatively high speeds.

[0020] Projecting from the interior of the bottom 13 of the cup 10 is a relatively short stud shown generally at 19. This interior stud fits relatively closely within center hole 21 of knot tuft retaining disk 12.

[0021] The disk 12 includes a center flat portion 22 surrounding the hole 19 and at its periphert has equally spaced up-turned projections or bent fingers shown at 23.

[0022] The fingers are each bent 90° through a radius corner shown at 25 with the corner having an exterior radius larger than the thickness of the disk. Each finger includes a wrap-around hole 26 which extends through the disk and completely through the finger curvature. Each hole has a diameter slightly wider than the curvature of the corner so that opposite sides of the hole radially of the disk are normal to each other as shown at 27 and 28. The inside of the hole 27 is parallel to the axis of the disk while the outside 28 is substantially radially spaced outwardly yet parallel to a radius of the disk and spaced axially of, or off-set from the flat portion 22

[0023] Between the bent fingers in which the wrap-around holes are formed are disk notches shown generally at 30, which provide openness and access to the inner ends or the loops of the twisted knots.

[0024] In construction a bundle of wires shown generally at 32 is threaded through the respective hole and then bent upon itself and twisted so that the individual filaments or wires spiral around each other as shown in 33. The individual tufts or knots are shown at 34. This operation forms a loop 36 at the inner end of each tuft or knot extending through the curved retainer disk hole.

[0025] After the knots are assembled to the retaining disk, the sub-assembly of the disk and knots is placed in the bottom of the cup so that the stud 19 extends through the center hole 21 of the disk. The tips of the filaments each extending in a slightly different direction from the working face 37. To secure the disk and knot assembly in place the top of the stud may be swaged or cold formed to form a rivet cap as indicated at 38 securing the sub-assembly in the cup with the knots or tufts projecting axially of the cup in rows uniformly around but inside the rim.

[0026] Because of the finger and notch construction of the disk, the inner ends of the knots at the loops are circumferentially equally spaced from each other while the plane of the loop is radial and the axis of the loop is circumferential. At this point the knots are supported only by the cup and the retainer disk. As indicated it has been proposed to support the knots by an inner sleeve or cup which may also be secured in similar fashion to the center stud 19. However, to achieve longer tool life and a more aggressive tool, I prefer to use a center plug or core 42 or 44 such as seen in FIGS. 3-7 to embrace more of the inner portion of the knot dampening unwanted wire vibrations particularly around the loop or inner portion of the knot substantially reducing long fractures and increasing tool life while significantly increasing the aggressiveness of the tool.

[0027] Referring now to FIGS. 3-6, the core 42 shown in FIG. 4 is made from a putty-like resin plug material while the core 44 shown in FIGS. 7 and 8 is made from a viscous liquid resin material.

[0028] In all of the embodiments illustrated the preferred material for the core is a non-metallic plastic, a relatively hard elastomer, or resin material, and preferably an epoxy compound. The preferred characteristics are a tensile shear strength of from about 600 to about 1200 psi, and preferably from about 800 to about 1000 psi. It should have a modulus of elasticity of about 6×10⁵, and a harness on the Shore D scale from about 60 to about 90, and preferably from about 70 to about 80. It should be able to withstand a use temperature of about 300° F., or more. The preferred epoxy is available in two part systems and can form intermediate mixtures in either putty or liquid form.

[0029] Referring initially to FIGS. 3-6, if a putty form is used such as seen at 42 in FIGS. 3-6, axial pressure on the core in such form may be provided by platen 45 or plunger 46 seen in FIG. 3. By applying force in the direction of the arrow 48, pressure on the top of the core during the assembly process will cause the core material to flow or extrude between the knots and down into the notches 30 in the disk embracing the interior of the knots within the cup.

[0030] In comparing FIGS. 5 and 6 it will be seen that the core material flows or extrudes between the knots as indicated by the core nodes 50 in FIG. 5. Continued or increased pressure will cause those nodes to flow between the knots embracing the knots to an even greater extent as at 52 in FIG. 6. Either form of embracement of the knot within the cup acts as a significant dampener reducing fatigue long fracture of the wire filaments, and substantially increasing both the life and aggressiveness of the tool.

[0031] In FIGS. 7 and 8 the core 44 material has been introduced in a relatively viscose liquid form and as can be seen, the core material almost completely surrounds the knot as indicated by the portion 54, and even flows through the notch 30 to extend beneath the disk 12 and substantially completely surrounds the loop 36, as indicated by the portion 56.

[0032] The tools seen in FIGS. 4-8 have been found to increase tool life by a factor of about two (2) and the aggressiveness of the three tool by a factor of about (3).

[0033] Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alternations and modifications will occur to others skilled in the art upon the reading and understanding of this specification. The present invention includes all such equivalent alterations and modifications, and is limited only by the scope of the claims. 

1. A twisted tuft knot type end brush having a cup, an annular row of twisted knot tufts projecting from the cup, and a center plug shaped to conform to and embrace the twisted knot tufts within the cup.
 2. An end brush as set forth in claim 1, wherein said center plug is a core of non-metallic material embracing the interior of the knots within the cup and having a tensile shear strength of from about 600 to about 1200 psi.
 3. An end brush as set forth in claim 2, wherein said material has a tensile shear strength of from about 800 to about 1000 psi.
 4. An end brush as set forth in claim 1, wherein said center plug is a core of non-metallic material embracing the knots within the cup and having a hardness of from about 60 to about 90 on the Shore D scale.
 5. An end brush as set forth in claim 4, wherein said material has a hardness of from about 70 to about 80 on the Shore D scale.
 6. An end brush as set forth in claim 1, wherein said center plug is a core of non-metallic material embracing the interior of the knots within the cup and having a modulus of elasticity of about 6×10⁵, and which will maintain its stability to about 300° F.
 7. An end brush as set forth in claim 1, wherein said center plug is a core of non-metallic material formed of epoxy resin.
 8. An end brush as set forth in claim 7 including a knot retainer plate secured in the bottom of the cup and having alternating fingers and notches, said core being applied in putty or liquid form and flowing between said notches to embrace said knots.
 9. An end brush as set forth in claim 8, wherein each finger includes an upturned radius bend, and a wrap-around hole in said bend, each knot including a loop extending through said hole in a plane radially of the cup, said notches enabling core access to the loop.
 10. A twisted wire tuft end brush comprising a cup having a bottom, a retainer secured to said bottom, said retainer including equally spaced projecting fingers with notches there between, each finger being bent to extend axially of the cup, a hole in the bottom of each of the bent fingers, a twisted knot tuft looped through each hole and extending axially of the cup.
 11. A brush as set forth in claim 10, wherein said fingers are bent 90° through a radius of curvature, said hole extending throughout said radius.
 12. An end brush as set forth in claim 10, including a non-metallic core in the center of the brush embracing the knots within the cup.
 13. An end brush as set forth in claim 12, wherein said core has a tensile shear strength of from about 600 to about 1200 psi, and a hardness on the Shore D scale of about 60 to about
 90. 14. An end brush as set forth in claim 13, wherein said core has a modulus of elasticity of about 6×10⁵, and will maintain its stability at about 300° F.
 15. A method of making a twisted knot wire tuft end brush comprising the steps of arranging and securing an annular row of twisted knot tufts projecting from a cup, and placing a center plug within the row of tufts to conform to and form a core embracing the twisted knot tufts within the cup.
 16. A method as set forth in claim 15 including the step of retaining the twisted knot tufts with a retaining disk having alternating fingers and notches, each finger being bent axially of the cup with a radius bend, each bend having a wrap around hole through which the wire tuft extends to be twisted to form the knot.
 17. A method as set forth in claim 16 including the step of forming a loop through the hole at the inner end of the knot.
 18. A method as set forth in claim 17 including the step of placing the center plug in liquid or putty form to extend through the notches to embrace the knots.
 19. A method as set forth in claim 15 including the step of placing the plug in putty form, and pressing on the putty to cause it to conform to the knots.
 20. A method as set forth in claim 15 including the step of placing the plug in liquid form, and flowing said plug to embrace the knots.
 21. A method as set forth in claim 15, wherein said plug solidifies to form a core having a tensile shear strength of from about 600 to about 1200 psi, and a hardness on the Shore D scale of from about 60 to about
 90. 22. A method as set forth in claim 21, wherein said core has a modulus of elasticity of about 6×10⁵ and which will maintain its stability to about 300° F. 